Organic compositions containing n-acyl benzotriazoles

ABSTRACT

Organic compositions, which are normally susceptible of corroding copper, are provided, containing, in an amount sufficient to inhibit such corrosion an N-acyl benzotriazole.

United States Patent Andi-cs5, Jr. et al.

[ Feb. 12, 11974 ORGANIC COMPOSITIONS CONTAKNING N-ACYL BENZOTRIIAZOILES Inventors: Harry J. Andress, .lr., Pitman;

Alfred B. liotrowski, Woodbury,

both of NJ.

Assignee: Mobil Oil Corporation, New York,

Filed: Apr. 17, 1972 Appl. No. 244,915

Related US. Application Data Continuationin-part of Ser. No. 163,093, July 15, 1971 abandoned.

US. Cl 44/63, 44/75, 44/64, 252/51.5 R, 252/77, 252/392 Int. Cl C10! l/22 Field of Search 44/63, 75, 64; 252/51.5 R, 252/77, 392; 260/308 B Primary Examiner-Daniel E. Wyman Assistant Examiner-Mrs. Y. H. Smith Attorney, Agent, or Firm-Andrew L. Gaboriault; Ray mond W. Barclay; Benjamin 1. Kaufman [5 7] ABSTRACT Organic compositions, which are normally susceptible of corroding copper, are provided, containing, in an amount sufficient to inhibit such corrosion an N-acyl benzotriazole.

16 Claims, No Drawings CROSS-REFERENCE TO RELATED APPLICATIONS Continuation-in-part of application Ser. 163,093, filed July 15, 1971 now abandoned.

BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to improved organic compositions and, in one of its aspects, relates more particularly to improved organic compositions in the form of liquid and solid hydrocarbon-containing materials'which normally tend to react with and corrode copper surfaces under conditions of use. Still more particularly, in this aspect, the invention relates to improved organic compositions in the form of lubricating oils, greases, fuels and solvents, which in their uninhibited state, tend to react with and corrode copper surfaces with which they may come into contact in performing their intended function.

' 2. Description of the Prior Art Prior to the present invention, benzotriazole has been employed in gear oils as a copper corrosion inhibitor. In such applications, it has been found that because of the very limited solubility of benzotriazole in mineral base oils, concentration of the benzotriazole can vary from 0.02 to 0.05 percent, by weight, and only if the benzotriazole is first dissolved in a suitable solvent. In instances where higher concentrations are required for combating extensive degrees of corrosion susceptibility, such increased concentration of the benzotriazole in the hydrocarbon medium, is not feasible. The prior art has suggested several methods by which the solubility of benzotriazole can be enhanced. These methods, for the most part, comprise either alkylating the aromatic nucleus of the benzotriazole or incorporating another functional group in this nucleus. Each of these methods, although feasible, was accomplished only with great difficulty and was associated with low yields.

SUMMARY OF THE INVENTION In accordance with the present invention, improved organic compositions, which are normally susceptible of corroding copper, are provided, containing, in an amount sufficient to inhibit such corrosion, an N-acyl benzotriazole, as more fully hereinafter described. These N-acyl benzotriazoles are found to be more soluble in hydrocarbon media than benzotriazole, itself, and still retain the copper corrosion inhibiting properties of benzotriazole. Thus, it is found that the N-acyl benzotriazoles are markedly effective as corrosion inhibitors in such organic media as gasoline,jet fuels, fuel oil, solvents, gear oils, hydraulic oils, turbine oils, cutting oils and greases. The N-acyl benzotriazole may be incorporated in any amount effective for inhibiting the degree of corrosion susceptibility of the organic composition. In most applications, the N-acyl benzotriazole is generally employed in an amount from about 0.001 to about 1 percent, and, preferably, in an amount from about 0.1 to about 0.5 percent, by weight of the total organic composition.

As herein employed, the term N-acyl benzotriazoles is intended to denote N-monoacyl, N-diacyl and higher acylated N-benzotriazoles.

A field of specific applicability of the present invention is in the improvement of organic liquid compositions in the form of petroleum distillate fuels and oils having an initial boiling point from about F. to about 135F. and an end boiling point from about 250F. to about l,000F. or higher. These distillate fuels and oils are not restricted to straight-run fuels and oils and can comprise straight-run distillates, catalytically or thermally cracked (including hydrocracked) distillate fuels or mixtures of straight-run distillate fuel oils, naphthas and the like, with cracked distillate stocks. Moreover, such fuels and oils can be treated in accordance with well-known commercial methods, such as acid or caustic treatment, hydrogenation, solvent refining, clay treatment and the like.

Particularly contemplated, among the fuels and fuel oils are those boiling in the gasoline range, jet fuels, domestic fuel oils, such as Nos. 1, 2 and 3 fuel oils, used in heating and as diesel fuel oils and turbine fuels. The domestic fuel oils generally conform to the specifications set forth in ASTM Specification D396-48T. Specifications for diesel fuels are defined in ASTM Specification D975-48T. Typical jet fuels are defined in Military Specification MIL-P 56243. Also included are gear oils, hydraulic oils and cutting oils.

In another field of specific applicability, the organic compositions improved in accordance with the use of the N-acyl benzotriazoles of the present invention, include any of the conventional hydrocarbon oils of lubricating viscosities which are capable of corroding copper. These may include mineral or synthetic lubricating oils, aliphatic phosphates, esters and diesters, silicates, siloxanes, oxalykyl ethers or esters. Mineral lubricating oils employed as the lubricating composition may be of any suitable lubricating viscosity and may range from about 45 SSU to about 6,000 SSU at l,000F., and preferably from about 50 SSU to about 250 SSU at 210F. These oils may have viscosity indexes from below 0 to about 100 or higher. Viscosity indexes from about 70 to about are preferred. The average molecular weight of these oils may be, for example, from about 250 to about 800.

As hereinbefore indicated, the aforementioned N- acyl benzotriazoles may also be incorporated as anticorrosion agents for copper in grease compositions. Such greases may comprise a combination of a wide variety of lubricating vehicles and thickening or gelling agents. Thus, greases in which the aforementioned N- acyl benzotriazoles are particularly effective may comprise any of the aforementioned conventional hydrocarbon oils of lubricating viscosity as the oil vehicle, and may include any of the aforementioned mineral or synthetic lubricating oils of the type indicated.

With respect to the formation of improved grease compositions in which the aforementioned N-acyl benzotriazoles are to be incorporated, the choice of employing a mineral or a synthetic oil of lubricating viscosity can best be determined from the nature of the intended environmental use for the grease. Thus, when high-temperature stability is not a requirement of the finished grease, mineral oils having a viscosity of at least 40 SSU at l00lF., and particularly, those falling within the range from about 60 SSU to about 6,000 SSU at F. may be effectively employed. In instances where synthetic vehicles are employed, rather than mineral oils, or in combination therewith as the lubricating vehicle, various compounds of this type may be successfully utilized. Typically, synthetic vehicles include: polypropylene, polypropylene glycol, trimethylol'propane esters, neopentyl and pentaerythritol esters, di-(-ethyl hexyl) sebacate, di-(2-ethyl hexyl) adipate, di-butyl phthalate, fluorocarbons, silicate esters, silanes, esters of phosphorus-containing acids, liquid ureas, ferrocene derivatives, hydrogenated mineral oils, chain-type polyphenyls, siloxanes (polysiloxanes), alkyl-substituted diphenyl ethers exemplified by a butyl-substituted bis(p-phenoxy phenyl) ether, phenoxy phenyl ethers, etc.

The lubricating vehicles of the aforementionedimproved greases of the present invention containing the N-acyl benzotriazole additive, are combined with a grease-forming quantity of a thickening agent. For this purpose, a wide variety of materials may be employed. These thickening or gelling agents may include any of the conventional metal salts or soaps which are dispersed in the lubricating vehicle in grease-forming quantities in such degree as to impart to the resulting grease composition the desired consistency. Other thickening agents that may be employed in the grease formulation may comprise non-soap thickeners, such as surface-modified clays and silicas, aryl ureas, calcium complexes and various other materials. In general, grease thickeners may be employed which do not tend to melt and dissolve when used at the required temperature within a particular environment; however, in all other respects, any material which is normally employed for thickening or gelling hydrocarbon fluids for forming greases, can be used in preparing the aforementioned improved greases in accordance with the present invention.

The N-acyl benzotriazole anti-copper corrosion additives are prepared in general, as more fully hereinafter described, by an acylation reaction in which equimolar amounts of benzotriazole, and an acyl halide are reacted in accordance with the procedure set forth in the following examples to produce the corresponding N- acyl benzotriazole.

More specifically, in accordance with the general procedure, to a mixture of benzotriazole (and preferably l or 2 moles of pyridine) in a suitable solvent (e.g. benzene, toluene or xylene) is added dropwise an equivalent amount of the acyl halide. After addition is completed, the reaction mixture is maintained at reflux conditions for a period of from about 1 to about 4 hours.

After the reaction mixture has been cooled, the pyridine hydrochloride formed is filtered off and the filtrate is concentrated. The resultant residue usually tends to solidify on cooling. This solid material is then broken up and washed with a solvent, such as n-heptane, nhexane or petroleum ether, to remove any residual pyridine. In instances where the aforementioned residue is in the liquid state, e.g. n-oleoyl benzotriazole, it can be distilled under reduced pressure.

DESCRIPTION OF SPECIFIC EMBODIMENTS The following examples will serve to illustrate the preparation of the n-acyl benzotriazoles of the present invention and their efficacy as copper corrosion inhibitors in organic compositions. It will be understood, however, that it is not intended that the invention be limited to the particular inhibitors or the particular organic compositions containing these inhibitors, as described. Various modifications of these inhibitors and organic compositions can be employed, as will readily be apparent to those skilled in the art.

EXAMPLE 1 Preparation of N-acetyl benzotriazole 1 mole (120 grams) of benzotriazole, 1 mole grams) of pyridine and 500 cc. of benzene are placed in a flask equipped with a stirrer, reflux condenser and thermometer. The apparatus is protected from moisture by drying tubes. To the above mixture in the reaction flask are added, dropwise, 1 mole (78.5 grams) of acetyl chloride. During this addition of the acetyl chloride, an exothermic reaction ensues. After the addition of the acetyl chloride is completed, external heat is applied to the reaction mixture to the point where a gentle reflux is attained. The reaction is then maintained at reflux conditions from 1 to 4 hours.

After cooling the solid pyridine hydrochloride is filtered off on a Buchner funnel, and the filtrate is then concentrated under vacuum. The residue, thus remaining, after concentration, tends to solidify on cooling. This solid is then ground and washed with n-heptane to remove any residual pyridine. The N-acetyl benzotriazole obtained by this method exhibits a melting point of approximately 51C. This compound is also described in the literature appearing in the Dictionary of Or ganic Compounds 4th Edition, Volume I (1965) Oxford University Press.

EXAMPLE 2 Preparation of N-butyryl benzotriazole Following the procedure described in Example 1, above, a mixture of 1 mole grams) of benzotriazole, 1 mole (80 grams) of pyridine and 500 cc. of henzene, is prepared. To this mixture is added 1 mole 107 grams) of butyryl chloride, in accordance with the above-described procedure. After cooling, filtration, grinding of the resulting solid material and washing with n-heptane to remove residual pyridine, N-butyryl benzotriazole is obtained, having a melting point of 55-58C.

EXAMPLE 3 Preparation of N-pivaloyl benzotriazole Following the procedure described in Example 1, above, a mixture of 1 mole (120 grams) of benzotriazole, 1 mole (80 grams) of pyridine and 500 cc. of benzene, is prepared. To this mixture is added 1 mole 120.6 grams) of pivaloyl chloride, in accordance with the above-described procedure. After cooling, filtration, grinding of the resulting solid material and washing with n-heptane to remove residual pyridine, N- pivaloyl benzotriazole is obtained having a melting point of 6870C.

EXAMPLE 4 Preparation of N-nonanoyl benzotriazole Following the procedure described in Example 1, above, a mixture of 0.5 mole (59.5 grams) of benzotriazole, 0.5 mole (40 grams) of pyridine and 500 cc. of benzene, is prepared. To this mixture is added 0.5 mole (81.0 grams) of nonanoyl chloride, in accordance with the above-described procedure. After cooling, filtration, grinding of the resulting solid material and washing with n-heptane to remove residual pyridine, N- nonanoyl benzotriazole is obtained having a melting point of 4243C.

' EXAMPLE 5 Preparation of N-oleoyl benzotriazole Following the procedure described in Example 1, above,- a mixture of 0.5 mole (60 grams) of benzotriazole, 0.5 mole (40 grams) of pyridine and 500 cc. of benzene, is prepared. To this mixture is added 0.5 mole (150 grams) of oleoyl chloride, in accordance with the above-described procedure. After cooling and filtration, the remaining liquid residue is distilled under reduced pressure and N-oleoyl benzotriazole is obtained having a boiling point of 2l5220/0.05 mm.

EXAMPLE 6 Preparation of N-stearoyl benzotriazole Following the procedure described in Example 1, above, a mixture of 1 mole (120 grams) of benzotriazole, l, mole, (80 grams) of pyridine and 500 cc. of henzene, is prepared. To this mixture is added 1 mole (303 grams) of stearoyl chloride, in accordance with the above-described procedure. After cooling, filtration, grinding of the resulting solid material and washing with N-heptane to remove residual pyridine, N-stearoyl benzotriazole is obtained having a melting point of 6064C.

EXAMPLE 7 Preparation of N, N-sebacyl benzotriazole Following the procedure described in Example 1, above, a mixture of 2 moles (240 grams) of benzotriazole, 2 moles (160 grams) of pyridine and 500 cc. of benzene, is prepared. To this mixture is added 1 mole (239 grams) of sebacyl chloride, in accordance with the above-described procedure. After cooling, filtration, grinding of the resulting solid material and washing with nheptane to remove residual pyridine, N, N- sebacyl benzotriazole is obtained having a melting point of l132C.

In order to demonstrate the efficacy of the N-acyl benzotriazoles of the present invention as copper corrosion inhibitors, a base blend was first prepared, in the form of a gear oil, comprising, by weight: 2 percent of a sulfurphosphorous load-support additive, containing 31 percent sulfur and 1.75 percent phosphorous; 2.25 percent of di-tertiary-butyl p-cresol; 0.2 percent polymethacrylate, as a pour depressant; 0.02 percent silicone defoamant; and the balance comprising 20 percent of a 200 SUS at 100F. neutral paraffinic solvent and 80 percent of a 150 SUS at 210F. solvent paraffinic bright stock.

The above-described base blend was next subjected to a series of copper corrosion tests for evaluation employing, in individual tests, the N-acyl benzotriazole additives prepared in accordance with the procedures of Examples 1 through 6. The test employed was the standard wet ASLE 64-9 Corrosion Test. In this test 50 grams of oil sample are placed in a 4 oz. bottle, to which are added 0.5 ml. of distilled water and the contents are vigorously stirred for about 1 minute. Clean polished pieces of copper are placed in the bottle. The bottle is then stoppered with a cork and placed in an electric drying oven for 24 hours, maintaining a temperature of 210 i 2F.

in accordance with ASTM D- rating, a rating of la or lb denotes a slight tarnish, a rating of 2a, 2b, 2c, 2d and 2e denotes a moderate tarnish; a rating of 3a or 3b denotes a dark tarnish; and a rating of 4a, 4b or 4c denotes corrosion. The individual comparative test results employing the N-acyl benzotriazole additives of the present invention are set forth in the following table:

TABLE ASLE 64-9 Corrosion Test Results Test Formulation Rating A Base blend 3b As will be apparent from the foregoing table, the base blend of Test A exhibited an unsatisfactory dark tarnish rating of 3b. On the other hand, the same base blend, but having incorporated therein 0.2 percent, by weight, of the specific N-acyl benzotriazoles of Examples 1 through 7, in Tests B through B, respectively, indicated improved and satisfactory copper corrosion inhibiting results.

While preferred embodiments of the compositions of the present invention, and specific N-acyl benzotriazole copper corrosion inhibitors, have been described for purposes of illustration, it will be understood that various modifications and adaptations thereof, which will be obvious to those skilled in the art, may be made without departing from the spirit of the invention.

We claim:

1. Organic compositions, normally susceptible of corroding copper, selected from the group consisting of liquid hydrocarbon fuels, lubricating oils, greases and solvents, containing in an amount sufficient to inhibit such corrosion, an N-acyl benzotriozole.

2. A composition in accordance with claim 1 wherein said composition comprises a liquid hydrocarbon se lected from the group consisting of gasoline, jet fuel and fuel oil.

3. A composition in accordance with claim 1 wherein said composition comprises a lubricant.

4. A composition in accordance with claim 1 wherein said composition comprises a gear oil.

5. A composition in accordance with claim 1 wherein said composition comprises a hydraulic oil.

6. A composition in accordance with claim 1 wherein said composition comprises a turbine oil.

7. A composition in accordance with claim 1 wherein said composition comprises a cutting oil.

8. A composition in accordance with claim 1 wherein said N-acyl benzotriazole is an N-monoacyl benzotriazole.

9. A composition in accordance with claim 1 wherein said N-acyl benzotriazole is an N-diacyl benzotriazole.

10. A composition in accordance with claim 1 wherein said N-acyl benzotriazole is present in an amount from about 0.001 to about 1 percent, by weight.

11. A composition in accordance with claim 1 wherein said N-acyl benzotriazole is present in an amount from about 0.1 to about 0.5 percent, by weight.

12. A composition in accordance with claim 1 sebacyl benzotriazole. 

2. A composition in accordance with claim 1 wherein said composition comprises a liquid hydrocarbon selected from the group consisting of gasoline, jet fuel and fuel oil.
 3. A composition in accordance with claim 1 wherein said composition comprises a lubricant.
 4. A composition in accordance with claim 1 wherein said composition comprises a gear oil.
 5. A composition in accordance with claim 1 wherein said composition comprises a hydraulic oil.
 6. A composition in accordance with claim 1 wherein said composition comprises a turbine oil.
 7. A composition in accordance with claim 1 wherein said composition comprises a cutting oil.
 8. A composition in accordance with claim 1 wherein said N-acyl benzotriazole is an N-monoacyl benzotriazole.
 9. A composition in accordance with claim 1 wherein said N-acyl benzotriazole is an N-diacyl benzotriazole.
 10. A composition in accordance with claim 1 wherein said N-acyl benzotriazole is present in an amount from about 0.001 to about 1 percent, by weight.
 11. A composition in accordance with claim 1 wherein said N-acyl benzotriazole is present in an amount from about 0.1 to about 0.5 percent, by weight.
 12. A composition in accordance with claim 1 wherein said N-acyl benzotriazole comprises N-acetyl benzotriazole.
 13. A composition in accordance with claim 1 wherein said N-acyl benzotriazole comprises N-pivaloyl benzotriazole.
 14. A composition in accordance with claim 1 wherein said N-acyl benzotriazole comprises N-oleoyl benzotriazole.
 15. A composition in accordance with claim 1 wherein said N-acyl benzotriazole comprises N-stearoyl benzotriazole.
 16. A composition in accordance with claim 1 wherein said N-acyl benzotriazole comprises N, N''-sebacyl benzotriazole. 